Magnetic lock and key



E M. RACTLIFFE MAGNETIC LOCK AND KEY Filed March 8, 1937 Patented June 21, 1938 PATENT OFFICE MAGNETIC LOCK AND KEY Edwin Merchant Rac-fliffe, Nottingham, England Application March 8, 1937, Serial No. 129,698 In Great Britain March 12, 1936 6 Claims.

This invention relates to a magnetic lock and key.

One object of the invention is to construct a lock and key of this kind, by which a large number of permutations and combinations may be effected so that the chance of any two being found exactly alike, is exceedingly remote.

Another object of the invention is to combine such a magnetic key with existing tumbler locks having the usual or conventional wards or pintumblers.

The invention consists in a magnetic lock and/or key wherein the key is provided with one or more magnets whose polarity ifiiar:

rangedthitWh'hithe key is inserted within the j il 993 the iqna netsa kupo one or more ma nets, constituting .feathers or cotteYs'aTfid normally locking the barrel to the mainpasing of the lock, in such a manner that said'leather or cotter magnets are repelled or attracted so as to free thebarrel and permit of its rotation relatively to the lgg k, follpherating thejatch.

The invention also consists in the further features hereinafter described and claimed.

The invention will now be described with reference to the accompanying drawing in which: Figure 1 is a longitudinal sectional elevation taken on the line I--I of Figure 2 of one embodiment of magnetic lock constructed according to,the invention, and in the locked position,

Figure 2 a cross section on the line 2-2 of Figure 1, drawn to a larger scale,

Figure 3 a similar view to Figure 1 showing the same look with the key inserted and in the unlocked position.

Figure 4 a cross section on the line I-4 of Figure 3, drawn to a larger scale,

Figure 5 a longitudinal sectional elevation of a modified form of lock, in the locked position. Figure 6 a similar view to Figure 5 showing the same lock with the key inserted and in the unlocked position,

Figure 7 a cross section of the modified form 5 of key used in the embodiment illustrated in Figures 5 and 6,

Figure 8 a longitudinal sectional elevation of a further embodiment of the lock with the key inserted and in the unlocked position, and. Figure 9 a longitudinal sectional elevation of the lock according to the invention applied to a tumbler lock.

Referring more particularly to the embodiment illustrated in Figures 1 to 4, the lock comprises a, fixed bushing I rigid with the lock casing and provided at its outer end with the usual circular face plate 2. Mounted within the bushing I is the barrel 3 the inner end 4 of which is connected in any well known manner to the latch bolt (not shown). 5 Formed in the periphery of the barrel 3 is a series of angularly disposed longitudinal grooves or recesses which in the example illustrated in Figures 1 to 4 comprise a single or upper groove 5 arranged midway along the length of the bar- 10 rel, and two sets of lower grooves 6 and I each set comprising a pair of grooves arranged one behind the other. A series of grooves or recesses 8, 9 and III, similar to the grooves 5, 6 and I formed in the barrel 3, are provided in 15 the inner surface or bore of the bushing I, the said grooves 8, 9 and II] being arranged opposite to their associated grooves 5, 6 and I when the lock is closed.

In this way, the associated grooves 5 and 8, 20 I5 and 9, 'I and I0, each forms a housing in which is positioned the bar magnets II, I2 and I3 respectively. The bar magnets I I, I2 and I3 normally rest under the action of gravity within the grooves 5, 9 and III, the magnet II resting 25 in the groove 5 in the barrel 3 and the magnets I2 and I3 in the grooves 9 and III in the bushing I. The depth of the grooves 5, 9 and I0, as compared with the depth of the magnets is such that the latter normally project out of 30 the said grooves into the grooves 6, I and 8, the magnet II projecting into the groove 8 in the bushing I while the magnets I2 and I3 project into the grooves 6 and I in the barrel 3. In this way the bar magnets II, I2 and I3 con- 5 stitute feathers or cotters-which normally lock the barrel 3 to the bushing I and thereby prevent the said barrel being rotated relatively to the bushing I and the fixed casing of the lock.

The key comprises a stem I4 having the usual 40 handle I5 secured to its outer end, and in the example shown in Figures 1 to 4, is of cylindrical cross section whereby it can be inserted with a sliding fit within the bore of the barrel 3. Within the stem I4 of the key, so as to be hidden 45 from view, there is provided a series of bar magnets I5, II and I8 similar to those locking the barrel 3 to the bushing I and positioned within said stem in a like manner so that when the key is correctly inserted the magnets I6, I I and I8 will be opposite the magnets I I, I2 and I3 respectively. In order to ensure that the magnets are brought opposite one another when the key is inserted into the barrel, there is secured to the stem I I of the key, a radial pin 55 I 9 which engages within a radial recess 26 formed in the front end of the barrel when the key is in the correct position.

The polarity of the bar magnets II, I2, I3 locking the barrel 3 to the bushing I, and their associated magnets I6, II and I8 in the key stem I4 is so arranged that when the key is inserted into the barrel 3 in the correct position as determined by the pin I9 engaging the recess 20, the upper associated magnets II and I6 repel one another while the two sets of lower magnets I2 and I1 and I3 and I8 are attracted. In view of the fact that the magnets I6, I! and I8 in the key stem I4 are fixed, the force of repulsion between the upper magnets II and I6 will drive the magnet II up into the groove 8 in the bushing I while the attractive force between the two sets of associated lower magnets I2 and I I, and I3 and I8 will cause the magnets I2 and I3 to be drawn upwardly into the grooves 6 and I in the barrel 3.

The depth of the grooves 6, I and 8 is greater than that of the magnets II, I2 and I3 so that the said magnets are raised clear of the periphery of the barrel 3 which is now free to be rotated relatively to the bushing I and thereby open the lock. In this connection it will be noted that the bore of the barrel 3 is formed eccentrically therein in order to provide a greater thickness of metal at the lower part of the barrel in which to form the grooves 6 and 7 which are deeper than the grooves 5 formed in the upper or narrower part of the barrel.

During the rotation of the barrel to open the lock the magnets II, I2 and I3 will ride upon the peripheral surface of said barrel and thereby be maintained in their respective grooves 8, 6 and I until the barrel is returned to its normal position with the grooves in alignment with the grooves in the barrel, whereupon the magnets II, I2 and I3 as soon as the key is withdrawn, will drop back, under the action of gravity, into their respective grooves 5, 9 and III and again lock the barrel 3 to the bushing I.

In the embodiment illustrated in Figures 5 and 6, the magnets and their associated grooves, instead of being disposed longitudinally are arranged radially. The bushing I has formed therein a series of substantially vertical grooves 2| which as shown are arranged one behind the other along the length of the bushing, but which may be angularly displaced relatively to one another if desired. Within the grooves 2I are slidably disposed bar magnets 22 which normally project, under the action of gravity, into grooves 23, formed in the periphery of the barrel 3 and arranged opposite the grooves 2| when the lock is closed. In the closed position of the lock as shown in Figure 5, it will be seen that there is a clearance space provided between the outer end of each of the magnets 22 and the outer end of its associated groove 2|, the depth of said clearance spaced being slightly greater than the depth of the grooves 23 in the barrel.

The key, which is substantially similar to that used in the embodiment illustrated in Figures 1 to 4, with the exception that the stem I4 is of flattened form as shown in Figure '7, has rigidly mounted within said stem a series of vertically disposed bar magnets 24 arranged one behind the other and corresponding in number to the magnets 22, the upper ends of the magnets 24 being arranged opposite the lower ends of the magnets 22.

The polarity of the lower end of each vertical magnet 22 and that of the upper end of each associated magnet 24 is such that when the key is inserted into the barrel in the correct position, by the engagement of the pin I 9 with the recess 20, a force of repulsion is set up between the adjacent ends of the two sets of magnets 22 and 24. The result of this force, in view of the magnets 24 being fixed, is to drive the magnets 22 outwards or upwards until they abut against the outer ends of the grooves 2|, in which position the lower ends of the magnets 22 are free of the grooves 23, formed in the periphery of the barrel which latter can now be rotated relatively to the bushing I in order to open the lock. During the rotation of the barrel, the magnets 22 are maintained in their raised position by the peripheral surface of the barrel and when the latter is rotated in the opposite direction to close the lock, the grooves 2I and 23 will again come into alignment so that when the key is withdrawn the magnets 22 will again drop, under the action of gravity, into the grooves 23, thereby locking the barrel to the fixed bushing I.

In the embodiment illustrated in Figure 8, horseshoe magnets are used in combination with bar magnets. The bar magnets 25 and 26 are arranged longitudinally in the manner already described in connection with Figures 1 to 4 and normally rest in grooves 21 and 28 formed in the barrel 3 and bushing I respectively. The depth of the grooves 2'1 and 28 is slightly less than that of the magnets 25 and 26, the magnet 25 pro- J'ecting beyond the periphery of the barrel 3 into a groove 29 formed in the bushing I, and the magnet 26 projecting beyond the inner surface of the bushing I into a groove 30 formed in the barrel 3, the depth of the grooves 29 and 30 being greater than that of the said bar magnets.

Within the key stem I4 is mounted a pair of horseshoe magnets 3I and 32 which are arranged with their pole pieces directly opposite the bar magnets 25 and 26 when the key is inserted as shown in Figure 8.

The polarity of the bar magnets 25 and 26 and their associated horse-shoe magnets 3I and 32 is such that a repelling action'is set up between the magnets 25 and 3I which forces the magnet 25 into the groove 29 in the bushing I, while an attractive force is set up between the magnets 26 and 32 which draws the magnet 26 up into the groove 30 in the barrel 3. In this way the barrel 3 is freed from the bushing I and can now be rotated to open the look. When the barrel is returned to its original position and the key withdrawn the bar magnets 25 and 26 will drop back into the grooves 21 and 28 under the action of gravity and lock the barrel 3 to the bushing I thereby retaining the lock in the closed position.

According to the embodiment illustrated in Figure 9, the invention is shown applied to a tumbler lock of the ordinary type provided with a bushing I having the usual face plate 2 and having an eccentrically positioned bore within which is fitted the barrel 3. In the upper or thicker portion of the bushing I there is provided a series of radial bores 33 while the barrel 3 is provided with a corresponding series of bores 34 which are normally in alignment with the bores 33 when the lock is closed.

Within each pair of associated bores 33 and 34 there is slidably mounted the usual tumbler pin 35 and driver pin 36 which pins are pressed inwards by the springs 31 so that normally each of the driver pins 36 extends from one bore 33 into the other bore 34 thereby locking the barrel 3 to the bushing I. When the key er-y I4 is inserted into the barrel as shown in Figure 9, the lower ends of the tumbler pins are engaged by the notches 38 formed in the upper edge of the key and are raised varying amounts according to the depth of the notches whereby the contact surfaces of the tumbler and driver pins are all made to coincide with the surface of the bore of the bushing and thus permit rotation of the barrel and consequently actuation of the lock.

In applying the invention to the type of lock above described, there is provided in the lower portion of the barrel 3, a pair of longitudinal grooves 39 which are arranged opposite a corres'ponding pair of grooves 40 in the bushing l. Slidably mounted within each pair of asociated grooves 39 and 40, is a bar magnet 4| which normally rests, under the action of gravity, in the grooves 40 which latter are of lesser depth than the magnets 4| which accordingly project above said grooves into the grooves 39 thereby locking the barrel 3 to the bushing Mounted in the lower part of the notched key stem I4 is a pair of bar magnets 42 which are arranged opposite the magnets 4| when the key is inserted into the barrel. The polarity of the associated pairs of magnets 4| and 42 is such that a force of attraction is set up between them which draws the magnets 4| up into the grooves 39 which are of greater depth than the said magnets, thereby freeing the barrel 3 from the bushing and permitting actuation of the look. When the barrel is returned to its normal position the grooves 39 and 40 will again come into alignment and as the key is withdrawn the magnets 4| will drop under the action of gravity, into the grooves 40 and lock the barrel to the bushing In this way a two-fold locking action is efiected, on the one hand by the mechanical action of the key upon the tumbler pins and on the other hand by the magnetic action of the key upon the bar magnets.

It will be understood that the invention is not limited to the particular embodiments above described which are only given by way of example as various other practical modifications may be adopted to carry the invention itself into effect, such modifications having to be considered as included within the ambit of the invention set forth in the appended claims.

For example, instead of the cotter magnets being retained in the locking position by gravity, they may be held in such position, against the action of gravity, by other magnets arranged in the bushing or the barrel of the lock, the magnetic influence of these other magnets being counteracted by the key magnets when the key is inserted into the barrel, whereby the cotter magnets are free to drop by gravity into the unlocking position.

I t will also be understood that by varying the longitudinal and radial positions of the magnets as well as their number, and also by changing the polarity of the magnets any number of alternative combinations can be obtained.

It will further be understood that the magnets can be either of round or rectangular cross section and similarly with regard to the key which can be of any regular or irregular cross section.

I claim:

1. A magnetic lock and key wherein there is formed in the periphery of the barrel a series of grooves which are normally in alignment with another series of grooves provided in the bore of the lock casing, each pair of associated grooves having slidably mounted therein a cotter magnet which projects into both grooves of each associated pair and thereby locks the barrel to the lock casing, the said cottor magnets, when the key is inserted into the barrel, being acted upon by the key magnets so as to be moved into a position in which each cotter magnet is wholly within one groove of each pair of associated grooves, whereby the barrel is freed from the. lock casing and can be rotated relatively thereto.

2. A magnetic lock and key as claimed in claim 1 in combination with the known tumbler lock, wherein the key which adjusts the tumbler pins so as to free the barrel is also provided with magnets which act upon the cottor magnets normally locking the barrel to the lock casing, whereby a two-fold unlocking action is effected, on the one hand by the mechanical action of the key upon the tumbler pins and on the other hand by the magnetic action of the key upon the feather or cotter magnets.

3. A magnetic lock and key as claimed in claim 1 wherein there is disposed around and in the periphery of the barrel at intervals along the length thereof a set of grooves which are normally in alignment with another set of grooves provided in the bore of the lock casing, each pair of associated grooves having slidably mounted therein a cotter magnet which projects into both grooves of each associated pair and thereby locks the barrel to the lock casing, one groove of each associated pair of grooves being of lesser depth than its corresponding magnet, whilst the other groove of each pair is of greater depth than the said magnet, the said cotter magnets, when the key is inserted into the barrel, being acted upon by the key magnets, so as to be moved into a position in which each cotter magnet is wholly within one groove of each pair of associated grooves, whereby the barrel is freed from the lock casing and can be rotated relatively thereto.

4. A magnetic lock and key as claimed in claim 1 wherein there is formed in the periphery of the barrel a set of grooves which are normally in alignment with another set of grooves provided in the bore of the lock casing, each pair of associated grooves having slidably mounted therein a cotter magnet, one groove of each associated pair of grooves being of lesser depth than its corresponding magnet whilst the other groove of each pair is of greater depth than the said magnet, each magnet normally resting under the action of gravity within that groove of each associated pair of grooves which is of lesser depth than said magnet so as to project partly into the other groove of each pair which is of greater depth than the magnet, thereby to lock the barrel to the casing, each magnet, when the key is inserted into the barrel, being caused to move wholly into the groove of greater depth through the magnetic action of the key magnets thereby to free the barrel from the lock casing.

5. A magnetic lock and key as claimed in claim 1 wherein there is formed in the periphery of the barrel a set of longitudinal grooves which are normally in alignment with another set of longitudinal grooves provided in the bore of the lock casing, each pair of associated longitudinal grooves having slidably mounted therein a cotter magnet which projects into both grooves of each associated pair and thereby locks the barrel to the lock casing, the said cotter magnets, when the key is inserted into the barrel, being acted upon by.the key magnets arranged longitudinally within said key, so as to be moved into a position in which each cotter magnet is wholly within one groove of each pair of associated grooves, whereby the barrel is freed from the lock casing and can be rotated relatively thereto.

6. A magnetic lock and key as claimed in claim 1 wherein there is formed in the periphery of the barrel a set of radial grooves which are normally in alignment with another set of radial grooves provided in the bore of the lock casing, each pair of associated radial grooves having slidably mounted therein a cotter magnet which projects into both grooves of each associated pair and thereby locks the barrel to the look casing, the said cotter magnets, when the key is inserted into the barrel, being acted upon by the key magnets arranged radially within said key, so as to be moved into a position in which each cotter magnet is wholly within one groove of each pair of associated grooves, whereby the barrel is freed from the lock casing and can be rotated relatively thereto.

EDWIN MERCHANT RACTLJFFE. 

